The barley Steptoe x Morex 150 doubled haploid line mapping population has been used to identify yield related quantitative trait loci (QTL) on chromosomes 2S, 3C, and 5L. We developed near isogenic lines (NILs) for each of these QTL regions as well as their combinations by transferring the Steptoe alleles into a Morex background or vice versus. The NILs were used for high resolution mapping of these QTL along with yield and yield related trait analyses. Major QTL for head shattering, lodging, number of rachis nodes and plant height were located in the chr. 3 QTL region. A major long daylength flowering QTL was identified on chromosome 2S and a short daylength flowering QTL was identified on chromosome 5L. These flowering QTL may be the same as the PpdH1 and PpdH2 loci previously identified in a different cross by Laurie and co-workers (Genome 38:575-585, 1995). Yield related traits i.e. plant height, number of rachis nodes, head shattering, and seed weight, were also associated with the chr. 2S QTL. Yield related traits were not found in the chr. 5L QTL region. Evaluations of isogenic lines in multilocational yield trials confirmed the successful introgression of the yield related traits, but did not demonstrate a significant yield increase in NILs over Morex. Our harvest conditions excluded losses due to lodging and head shattering, thus it is possible that a yield advantage over Morex would have been noted under more ÒtypicalÓ agronomic harvest conditions. Alternatively, these QTL need to interact with other, Steptoe specific, genes in order to be fully functional. A non-lodging, non-head shattering Morex derivative was produced that retained all Morex malting quality traits.